have been simplified or modified to fit game mechanics, and also better gameplay. World of Tanks has five different types of vehicles: light tanks, medium tanks, heavy tanks, tank destroyers, and self-propelled artillery. The game currently includes over 600 armored vehicles from Britain, China, Czechoslovakia, France, Germany, Italy, Japan, Poland, the Soviet Union, Sweden, and the United States. Each nation has a tech tree with at least one branch of vehicles ranging from tier I (lowest) to tier X; players progress by playing games in vehicles in a branch. Additional premium and collectors' vehicles are available outside the tech trees for cash or in-game credits. All vehicles can be customized to a certain degree, either visually or in terms of performance, with the majority of parts (such as tracks, guns, turrets, and engines) being modular parts purchased from the game's tech tree. Various two-tone and three-tone camouflage schemes are available for all tanks as well, including both historically accurate patterns and game-specific, custom variants. Camouflage is available for temporary use by paying with freely earned in-game credits, or for permanent use by paying with gold purchased in the World of Tanks store or won in an in-game event. Players can apply national flags, pre-designed slogans, and camouflage (that will slightly increase the chance of remaining undetected). All vehicles can mount three pieces of additional equipment, which vary from vehicle to vehicle, and offer various advantages. Some equipment allows the gun to fire faster, some increase the durability of certain parts of the vehicle, and some help keep the vehicle hidden while stationary. Each vehicle can carry three consumables. Examples of these include repair kits, medical kits, fire extinguishers or nation-specific extra rations that boost the tank's crew for the duration of a single battle. Clan Wars Clan Wars in World of Tanks has two main components: Strongholds and the Global Map. Each clan can have its own stronghold, if the clan's commander wishes to construct one. Each stronghold begins with one zone and can grow to up to four zones as the clan's membership increases. Many different types of structures exist; however, only one of each can be built. By consuming industrial resources, some structures generate special missions or reserves that can be used to temporarily boost clan members' experience or credits or enable artillery or airstrikes during a battle for a stronghold. To build structures, industrial resources are required,